Violet cotton-dyes.



UNITED STATES A'O'GUST LEOPOLD LASKA, OF OFFENBACH- CORPORATION OF CHEMISOHE FABRIK- THE-MAIN, GERMANY.

VIOLET COTTON-DYES.

N 0 Drawing.

To all whom it may concern:

Be it known that I, AUGUST LnoroLp Lassa, doctor of philosophy, chemist, a citi- Zen of the German Empire, and resident of Offenbach-on-t-he-Main, in the Grand Duchy of Hesse, Germany, with post-office address \Vilhelmsplatz 18, have invented new and useful- Improvements in Violet Cotton- Dyes, of which the following is a specificatic-n.

By my invention very valuable violet cotton-dyes are obtained by combining the tetrazo derivative of the meta-meta-disul tonic acid of para-para-diamino-diphenylurea with two molecules of a 2-arylamido-5- naphthol7-sulfonic acid in alkaline solution.

The new dyestuffs probably have the formula:

SO Na,

specific gravity and let parts of sodium nitrite. The tetrazo compound, thus obtained, is poured into a solution of 68 parts of the sodium salt of 2-phenyl-amino-5 naphthol-7-sulfonic acid, maintained alkaline until the combination is finished. 1V hen Specification of Letters Patent.

applicationfiled August 27,1912. Serial No. 717,244.

metzV-disulfonic acid of Patented Dec. 31, 1912.

the production of the the mixture is heated to 60 (1., and the dyestufl is precipitated by adding salt. It yields, when dry, a brownish black powder, soluble in concentrated sulfuric acid to a violet blue solution, in water to a reddish violet solution. From this solution the dyestuli is precipitated by concentrated hydrochloric acid in bluish violet flakes. It dyes cotton very pure reddish violetoring only a little on soaping also washed white cotton.

Upon reduction with stannous chlorid and hydrochloric acid the dyestuffs yield metapara-para-diamin0- diphenyl-urea and 2-arylamino-5'-oXy-6- aminc-naphthalene-T-sulfonic acid. A like procedure may be adopted when making dyestuffs from other 2-arylamino-5-naphthol-7sulf0nic acids.

Now, what I claim and desire to secure by Letters Patent, is the following:

1. As new products, the hereindescribed azo dyes, having probably the formula:

SOnNa OH so ua wherein 1% means an aromatic radical, the said azo dyes being brownish black powders, soluble in concentrated sulfuric acid to a violet blue solution, in water to a reddish blue solution, dyeing cotton very pure violet shades and yielding upon reduction with stannous chlorid and hydrochloric acid the meta-meta-disultonic acid of para-parafdiamino-diphenyl-urea and 2-arylamino-5- oxy-G-amino-naphtha1ene-7-sulfonic acid.

shades, col- 2. As a new product the herein described azo dyestuii, having probably the formula:

some

soma OH the said dyesiuif being a brownish 'black powder, soluble in concentrated sulfuric acid to a violet blue solution, in Water to e red- (llSll blue solution, dyeing cotton very pure violet shades and yieldin upon reduction with stannous chloi'id end liydrochloric acid the metwmeta disulfonic acid of para-poredia'lnino-dipl1enyl-urea and Q- henylamino- 5-oXy-6-amino-naphthalene-7-sulfonic acid.

In testimony, that I claim the foregoing my invent-ion, I have signed my presence of two witnesses, this l ith day of August 1912.

AUGUST LEGPOLD LASKA'.

Witnesses:

PETER LnU'rEN somilionn, FRITZ Diison.

Comes of ahis patent may be obtained for five cents each, by aiidressing the Commissioner of Ifatents, Washington, D. Q!

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